Color comparator



Feb. 15, 1 944. e. D. PEET COLOR COMPARATOR Filed Sept. 30, 1941 2Sheets-Sheet 1 INVENTOR. 1]. Reel BY W, Km 1 fierald ATTORNEYS Feb. 15,1944. I e. D. FEET coL R COMPARATOR Filed sept. 50, ,1941

2 Sheets-Sheet 2 INVENTOR. fierald .3. Peei Y CO' THA, Km '6' ATTORNEYSMIN Patented Feb. 15, 1944 2,341,810 COLOR comrsnuon Gel-am 1). Peat,Montclair, N. J., assignor to Wallac e & Tiernan Products, Inc.,Belleville,

N. J., a corporation of New Jersey Application September 30, 1941,Serial N 0. 413,050

6 Claims.

. nation may be unavailable or unreliable.

A primary purpose of these instruments is for determining, as by theso-called ortho-tolidin test, the free or residual chlorine content ofwater that has been treated with chlorine to purify the water fordrinking or other purposes, and the apparatus of the invention is ofparticular utility in emergency or field conditions where temporarywater supplies must be chlorinated for immediate use as by means ofportable or mobile equipment. Further objects are to provide a sturdybut economical structure for an illuminated color comparator; to avoidthe inaccuracy or unreliability sometimes attendant upon the use ofdevices that are illuminated by natural light, which may vary widely; toprovide a device requiring infrequent and indeed almost no attention forrenewal of lamps or batteries; and to provide a completelyself-contained instrument which is light in weight, convenient tooperate and susceptible of use under an infinite variety of conditions.An-

other object is to provide a portable, illuminated comparator of suchcharacter that it may be used, for example by military forces in theopen at night, and while affording satisfactory illumination for itsoperation, will shed or emit no surplus light for detection by enemyaircraft or other observers.

To these and other ends, such as will be hereinafter stated or apparent,or suchas are incidental to the described features and combinations, anadvantageous and presently preferred embodiment of the invention is setforth, by way of example, in the accompanying drawings. Referring to thedrawings:

Fig. 1 is a perspectiv strument;

Fig. 2 is a plan view; i

Fig. 3 is a side elevation, looking toward the lower side of Fig. 2, butwith certain parts cut away, or in section generally on line 3-3 of Fig.2;

view of the complete in Fig. 4 is ahorizontal section on line 44 of Fig.

Fig. 5 is an inside elevation of the rear cover of the device, showingthe parts attached there- Fig. 6 is a section on line 6--6 of Fig. 5;and

Fig. 7 is a fragmentary section on line 1-1 of Fig. 2.

It will be observed that certain features of the instrument,particularly the arrangement of liquid containers, color disk andviewing prisms, are identical or substantially identical with the deviceillustrated and described in my aforesaid Patent No. 1,976,672; to whichreference may be had for a more complete description of these elementsand their associated mounting or retaining Darts.

In general, the structure comprises a pair of spaced walls or platesIII, II, on opposite sides of a casing structure I 2 which includesvertically extending compartments I 3 and M respectively holdin'g glasscontainers of the liquids to be compared, and 'a further verticalcompartment l5 which may removably retain a supply bottle of suitablereagent or indicator of which a portion is added to one of the liquidsamples for the purpose of color comparison. A color standard disk It ismounted to rotate on the cylindrical flange I8 of the casing l2 andbeneath the cover plate l0, so that a central glass plate l9 of standardcolor (i. e., standard light-transmitting character) is maintainedcontinuously in front of an aperture 20 for the compartment l4 and anyone of a series of 'variously colored standard glasses 22, may beselectively presented according to the rotation of the disk, in front ofa like aperture 24 for the compmment l3.

As more fully explained in my aforesaid patent, the disk I6 is providedwith a series of index numbers which give readings of chemicalcomposition corresponding to the several color standards 22,

. -and which are so disposed as to be'successively ,visible through anaperture 26 in the cover plate it. An eye piece or viewing devicecomprising a light excluding casing 21 and a magnifying lens 28, isdisposed in front of suitable apertures in the cover plate whichregister with the windows 21!,v 24, for simultaneous observation of thetwo liquids as seen through the standard glasses or color filters I9,22. For better comparison, the viewing device includes a pairof prisms29. 30, so that the two bodies of liquid are seen as if fullyjuxtaposed.

As the device is shown in the liquids in the containers 3!, 32 of therespecmy aforesaid patent,

tive compartments l3, l4, are illuminated by light through a window 33(comprising a milk-glass or other suitable difiusing pane) in the rearwall II, and as the operator looks through the eye piece, the disk I6 isrotated until the two liquids, as seen through the standard l9 and oneor another of the standards 22, seem the most alike in color. Thus ifthe two containers hold samples of the same liquid, and if a suitableindicator or the like, for example, has been added to the liquid incontainer 32, to produce a color representative of the chemicalcondition of the liquid, the condition of equality as seen through theeye piece will be represented by a suitable number. in the indexposition 26, which then affords the desired reading of the chemicalcomposition of the liquid; and coloring other than that due to theindicator is balanced out.

It will be understood that the colors of the standard It and theselectable standards 22 are chosen or calibrated, so to speak, foranticipated or likely conditions of use. For instance, the selectablestandards or light filters 22 may be a graduated series of colors equalor corresponding to possible color efiects produced by the indicator inthe liquid. While in some cases the standard color" l9 may be simplyclear glass, it may be preferable in many cases, as to permit moreaccurate coloring of the selectable standards, or for other reasons. tohave the central standard I!) of a predetermined light-modifying coloror shade, which is then balanced out, so to speak, in each of the otherstandards 22.

It may be noted that suitable means, such as the spring structure 9|,92, may be employed to hold the containers 3|, 32 and the reagentbottle, removably in place in their respective chambers l3, l4 and |5-asmore fully described in my aforesaid patent.

Although useful for pH readings or for a wide variety of othercolorimetric determinations, the instrument is of special importance fordetermining the chlorine content of water which has been purified bytreatment with chlorine. To

that end an appropriate reagent solution is supplied in the bottle inchamber l5, such as orthotolidinwhich produces a yellow color of varyingcharacter dependent upon the amount of chlorine actually remaining inthe water. It will be understood that to insure that 9. tion has takenor is taking place, for example for purposes of drinking water, thewater, after treatment, should have a certain minimum content of free orresidual or otherwise still available chlorine. At the same time, fromthe standpoint both of economy and taste, it is undesirable to have agreat deal more than the prescribed and ordinarily very minute minimumamount of chlorine in the treated water. For these determinations thescale or index figures on the color 60 shaped structure of disk may readsimply in parts per million of chlorine, the color standards beingdesigned and calibrated to indicate various chlorine concentrationsbelow, at and above the desired optimum value.

In accordance with the present invention, the illustrated apparatusincludes a further lighttight casing generally designated 4|! andcomprising a rectangular body or wall portion 4|, and a rear cover plate42. The body 4| is peripherally congruent with the main casing l2 and ismounted against the rear wall ll ofthe latter (to enclose the window33), as by suitable screws 43 threaded into integral cornerreinforcements 44 of the body 4|. To avoid corrosion, both parts of thecasing 40 may conveniently be made of suit- 76 ing at one side curvedlocation and to insure the exclusion of light, the

cover 42 has a flange 41 which periphery of the shoulder 48 on the seatsaround a corresponding wall portion 4|.

A pair of vertical walls 50, 5|, and a horizontal wall 52 joining them,extend integrally from the cover plate 42 and in cooperation with anadjacent portion of the side wall structure 4|, provide a lamp chamberwhich opens upon and registers with the window 33. ,The inner surface ofthis chamber may be painted white or otherwise treated or lined toprovide maximum and preferably difiuse reflection of light toward thewindow. Mounted in the chamber to hold a bulb 55 having a miniature (e.g., standard flashlight) base for illuminating the window 33, is a smallsocket 56, which has its supporting post 51 threaded into a nut 58embedded in a suitable boss on the inside of the cover plate 42. l

The cover plate 42 also has (see particularly Figs. 3, 5 and 6) meansfor carrying a source of current for the shown, this structure consistsof a pair of devices each adapted for removably retainin a small drycell, as of the flashlight type. Each device com prises a clip having aflat longitudinal base portion 60 screwed to a reinforced supportingframe 6| extending integrally inward from the cover plate 42; theturned-up ends of the clip consist respectively of a ring-shaped portion62 at one end and an arm 63 at the other. Mounted on the arm 63 andinsulated therefrom by a suitable bushing 64, a opposite end 62 of theclip, electrical connection being made to the disk by its mounting rivetor screw 66. The elements 62, 3 are resiliently that a small flashsize0, 1% inches biased toward each other so light cell 61 (e. g., Evereadydesired steriliza- 0 long) may be inserted and held between them byspring pressure, good electrical contact being thus made between theelements and the opposite ends of the cell.

The ring portion 62 of each clip is preferably convexly toward the cellend, about an axis parallel to the clip base, as shown in Pig. 5, tofacilitate insertion of a cell, and it will be noted that withoutsacrifice of resilience or of strength due to thickness of material thering-' the part 62 likewise facilitates cell replacement (by reducingthe stillness of the clip) and at the same time promotes electricalcontact. Moreover, the illustrated clip structure insures insertion ofcells in proper direction, it being immediately apparent to the userthat the flat negative end of the cell container must go against thering 62 and the opposite positive pole against the contact button I. Itwill be noted that both of the cell holders are alike, but forcompactness and convenience in wiring are disposed in oppositedirections and on opposite sides of the illuminating chamber, parallelwith the longer sides of the latter.

The socket 56 has a connecting lug ll extendthereof, and anotherconnecting lamp, within the casing 40. As

concave contact disk 65 faces the ation of the stud 84 and th slotprovides lug H, conveniently connected to the shell of the socket andinsulated from the supporting shank 51, extending toward the inner wall52 of the illuminating chamber. The lugll may comprise a relativelyrigid plate and be disposed above the slightly upturned end 12 of acontact spring 13 which is mounted on a raised portion 14 of the coverplate 42, the mounting of the spring being advantageously in the spaceon the cover plate beyond the wall 52, and the latter having a suitableaperture through which the spring 13 extends. A push button or stud 15extends through a hole in the-cover plate 42, as shown in Fig. 4. and isadapted to engage the side of the spring 13 and push its upturnedportion 12 into contact with the plate H. The operating face 16 of thebutton 15 is sunk in a suitablerecess in the outer surface of the coverplate and an inner retaining flange may be so positioned on the stud, asshown,

that the button face '76 cannot move out beyond a position slightlyrecessed from the outer surface of the plate 42.

By suitable conductors extending, as shown in Figs. 3 and 5, to the clipbases 60 and their positive terminals 66, the cells are connected inseries between the socket lug 1.0 and the contact spring 73; and thusthe circuit to the lamp 55 is normally held open by the resilience ofthe'spring, but may be closed to light the lamp by pushing the button15. A spare bulb may also be carried in the casing 40, as in the coiledwire holder 19 mounted on the outer side of the wall 52, as shown.

It will now be seen that for replacement of batteries or bulb, or forother attention, the casing 40 is opened simply by removing the screwsand taking off the cover plate 42. All of the en--' closed structure isconveniently attached, as explained above, to the cover plate, so thatupon removal of the latter, everything is fully and instantlyaccessible. It will also be noted that the walls 50, SI, 52 of the lampchamber and the several supporting frames and projections for the otherparts described are all molded integrally with the cover plate, 1. e.,the latter may thus be manufactured inexpensively as a one-piecestructure by a single molding operation. The wall or body portion 4| maylikewise be molded in one piece, including all fourwalls and thedescribed corner reinforcements, with'like advantages of economy andease of manufacture.

The casing 40 also serves to support'the movablelight-confining meansnow to be described. At the op of the assembled device (Figs. 1, 2,

3 and 7) there is pivotally mounted a plate which is disposed flat-wiseand when swung into the positionshown in Fig. 1 is adapted to covercompletely the upper ends of both the chambers l3, l4. This plate, whichmay be made of metal, or, if desired, 01' corrosion-resistantmaappropriate stops,'at the ends of the slot, for movements of the plate80 between its open position of Fig. 2 and its closed orlight-interrupting position of Fig. 1. At the same time the springpressure urging the inwardly tapered head of the stud against the upperedges of the slot, holds the plate 80 in satisfactorily flat-wiseengagement with the upper surface of the apparatus, and exertssuflicient friction to keep the plate from swinging accidentally whilepermitting manual movement when desired. By virtue of the conformity ofthe upper surface of the casing 40 and that of the forepart of theapparatus to be covered, the plate 80 is held flat against a supportingsurface or structure in the same plane at all times in its permittedrange of movement andthus there is no danger of the plate being bent outof shape so as to impair its light-confining function, as nright easilyoccur if any substantial part of it were permitted to extend free of asupporting surface or framework. It will now be seen that when thecontainers 3|, 32 have been filled for test and the plate 80 has beenmovedover as shown in Figs. 1 and 3, escape of illumination from theupper ends of the chambers l3, I4 is effectively prevented.

To complete the light-sealing arrangement, an exactly similar pivotedplate structure 8011 is disposed on the similarly flat underside of thep apparatus, and mounted by a pivoted screw flla terial (and which maybe black in color, like the rest of the apparatus except the inside ofthelamp chamber), is pivoted at a'corner of the I casing wall part 4|adjacent the juncture of the latter with the wall II, by means of ascrew 8| threaded into the adjacent reinforcing portion 44- and havingan enlarged upper shank 82 to provide a bearing for the cooperating holein the plate 80 Fastened beneath the head of the screw and extendingtransversely from it, isa short spring strip 83 carrying a downwardlyprojecting stud 84 which passes freely through an arcugte slot 85 in theplate 80 and conveniently extends into a slight recess 86 in the uppersurface of the casing wall 4| The cooperand short spring 83a in exactlythe same fashion as the plate 80, so as to be movable into and out ofcorresponding position for'covering the open lower ends of both thechambers 13, I4.

By virtue of its reliable and easily operated light-confining structure,the instrument is particularly valuable for use by military forces inthe field, or for other emergency use in wartime, and obviates the;danger of showing light to enemy aircraft or other observers. At thesame time, the illuminating structure, including the casing 40 and theinstrumentalities and combinations thereof as described, cooperate toprovide a simple and highly'efl'lcient. illuminated comparator. Inmilitary operations, for example, where supplies of drinking water mayoften have to be established at night'or under other condititons ofurgency, the device isexceptionally convenient for testing the water anddeter.- mining its purification as by chlorine treatment. All that isnecessary is to fill the containers 3|,

32 with treatedv water-the container 32 to aat the index window 26. Toavoid any need for use of visible exterior illumination, the index'numerals seen through the opening 29 may be printed with a luminous or,radium paint, or they may be printed with a fluorescent ink which can beread with so-called "black light. i. e., radiation of a wave-lengthoutside the vise ible spectrum; or in some cases, the indexnumbers maybe printed directly on the glasses 22.1 It will be noted that not'onlyis the spring push button arrangement adapted to save current and thusprolong the life of the battery, in that the current is only turned onso long as the button is pushed, but the recessed structure of 'thebutton prevents inadvertent closure or the circuit should the adjacentwall 42 rest or, as in a carrying case, be urged against some othersurface. .As previously explained, the apparatus may be readily openedfor adjustment or replacement of portions of the illuminating structure;and yet the whole device is complete in itself, and is sufllciently ruged and reliable to withstand rough handling and to perform its expectedhealth-guarding function whenever used for illumination of a colorcomparator, to

reduce its sensitivity to small differences in color produced by theindicator in the liquid under test, or even to modify the colorrelations in such way as to produce false readings. The present deviceaifords a constant illumination of desired intensity and spectralcharacteristics (preferably, for example, the bulb 55 is of the"daylight type, i. e., daylight-simulating), so that all suchdifilculties are avoided and the calibration of the instrument isuniform and accurate for all conditions of use. The movablelight-interrupting plates 80, 800 also cooperate to that end, even whenthe device is used in daytime, in preventing impredictable variationsdue to stray light coming through the ends of chambers l3, l4, andreflected or refracted by the glass containers or by the liquid or bymatter suspended in the liquid. At the same time, the apparatus is allself-contained in a small, readily portable instrument, (in a commercialexample of the device, the structure included by the covers I0, 52measures 3%" x 3%" x 4", with the eyepiece in proportion), and theilluminating and light-confining means are so constructed that they maybe easily added as a unit, if desired, to existing devices such as areshown in my aforesaid patent.

It is to be understood that the invention is not limited to thestructure and arrangement herein shown and described, by way of example,but may be embodied in other forms without departure from its spirit asdefined by the following claims.

I claim:

1. In a color comparator comprising a pair of vertical chambers, meansin each for removably retaining a transparent liquid container, saidchambers being open at both ends to facilitate insertion and removal ofthe containers, a wall common to said chambers and having a window foradmission of light thereto, viewing means for observation of lightpassing through the chambers from the window and means intermediate saidviewing means and said chamhers for selectively disposing one of a'plurality of predetermined color filters intermediate one of saidchambers and said viewing means, the combination of an opaque casingmounted to the device forenclosins said window. said casing comprising aremovable part, an electric lamp mounted on said removable part forillumination of said window, means carried by said removable part forremovably retaining electric cell means, a switch in said casing havingan operating member extending through the wall of the casing for accessexteriorly thereof, said switch being biased to open position and beingadapted, upon depression her, to connect the cell means with the lamp,

said operating member being recessed in said casing whereby its outerextremity is below the outer surface of the casing, a cover platepivoted to the casing and adapted to be swung into and out of positionfor covering the aforesaid chambers at one end against escape of lightplate pivoted to the casing and adapted to be swung into and out ofposition for similarly covering the opposite ends of the chambers.

2. In a portable color comparator for colorimetric inspection of liquidmaterial, which includes a pair of adjacent open-ended chambers eachadapted to receive and removably retain a transparent container forliquid to be inspected, window means at one side of said chambers foradmitting light through the same, and viewing means on the opposite sideof said chambers, the combination of enclosed means for illuminatingsaid window means, including an electric lamp and electric cell meansfor energizing said lamp, switch means for connecting said cell meanswith said lamp at desired times, and shiftable light-excluding covermeans adapted to be moved to enclose said open-ended chambers forpreventing escape of light therefrom and shiftable out of said positionfor access to said chambers.

3. In a color comparator having mutually spaced window and viewingmeans, means holding in the path of light intermediate said window andviewing means, a plurality of samples of liquid and a selected colorstandard, for simultaneous-comparative observation of one of said.

samples with another of the samples asmodifled by the color standard,said comparator having a rear wall which includes said window means butwhich has an opaque-portion of substantial area, the combination of alight-excluding casing enclosing said window means,a compartment in saidcasing opening on said window means and 'having light-reflectinginterior surfaces, a lamp said cell-retaining means, switch and socketwhereby'the switch may be operated to, light a lamp in the socket forilluminating the windo means. v v

4. In a color comparator for colorimetric inspection of liquid material,in combination, a casing having a smooth upper surface, a verticalchamber opening at said surface for removably receiving a containerofliquid to be inspected, light-producing means contained in the casingfor directing illumination to the of said operating memchamber, a coverplate upon and substantially conforming to the upper surface of thecasing, and means pivotally mounting said plate for swinging movementacross said surface into and out of position for covering the opening ofthe chamber.

5. The comparator of claim 4, wherein the casing has a similarly smoothunder surface, and wherein the vertical chamber opens at the undersurface as well, to facilitate manually pushing a container up out ofthe chamber, and which includes a cover plate beneath and substantiallyconforming to the under surface 'of the casing and means pivotallymounting said plate for swinging movement across said under surface intoand out of position for covering the lower opening of the chamber.

6. In a color comparator having a. housing .with a flat upper surface, avertical chamber opening at said surface for removably receiving acontainer of liquid to be inspected, and a vertical wall having a windowfor admission of light to the chamber, the combination of an open-backedcasing mounted against said wall and having a flat upper surface flushwith the upper surface of the comparator housing, a c'over removablyattached to the back of said casing, clip means carried on the inside ofsaid cover for removably holding electric cell means,

a lamp socket mounted on the inside of said cover for holding a lamp toilluminate the window, aswitch on said cover spring-biased to openposition and having an operating member accessible exteriorly of thecover, means for electrically connecting the clip means to the socketwhen the switch is operated, a light-interrupting plate, means pivotingthe plate at a comer thereof to the upper casing surface whereby theplate may be swung flatwise, against said surface,'to and from aposition to cover the opening of the vertical container chamber, anarcuate slot in the plate about the pivoting means, and a fixed memberextending radially from the pivot and having a projection frictionallyentrant into the slot, for urging the plate flatwise against the uppersurfaces of the housing and casing and arresting displacement of theplate at the ends of the slot.

GERALD D. PEET.

